Diagnosis
This is almost always a setup timing issue or a band problem. The unit's WiFi only works on a 2.4 GHz network, and the setup process has a very specific sequence you have to follow.
How to Fix It
1) On the unit, hold the WiFi button for 3 seconds until the light blinks rapidly. 2) Immediately go to your phone's WiFi settings and connect to the network named something like "GE_Dehumidifier_XXXX". 3) Then open the SmartHQ app and follow the prompts. The key is connecting your phone to the dehumidifier's signal before you try to use the app for setup.
If That Didn't Work
Your home router might be broadcasting a combined 2.4/5 GHz signal with the same name. Log into your router settings and temporarily create a separate, dedicated 2.4 GHz network with a different name (like "Home_2G"), then try the setup process again connecting to that new network.
Heads Up
Once set up, if the unit loses power, it can sometimes lose its WiFi connection and you have to repeat this entire setup process. Plugging it into a smart plug that you can cycle on/off remotely can save you a trip to the basement if that happens.